1. Field of the Invention
The present invention relates to a gate drive circuit, a display substrate having the gate drive circuit, and a method thereof. More particularly, the present invention relates to a gate drive circuit capable of enhancing reliability, a display substrate having the gate drive circuit, and a method of enhancing reliability of the display substrate.
2. Description of the Related Art
Generally, a plurality of display cells is formed on a mother substrate, and then the mother substrate is separated into a plurality of display substrates through an array test process and a scrap process.
A plurality of test pads for performing the array test process for each of the display cells is formed in the mother substrate. The test pads are electrically connected to a plurality of data lines and a plurality of gate lines that are formed on each of the display cells. The test pads include a plurality of test pads applying a data test signal to the data lines and a plurality of gate test pads applying a gate test signal to the gate lines.
Recently, a display substrate having a gate drive circuit for driving the gate lines integrated thereon has been developed. The gate drive circuit includes a plurality of stages outputting a gate signal to the gate lines. When the gate drive circuit is integrated on the display substrate, a plurality of drive signals for driving the gate drive circuit is applied to the gate test pads.
The drive signals include a power signal VSS, a plurality of clock signals CK and CKB, and a vertical start signal STV. The power and clock signals VSS, CK, and CKB are provided to each of the stages of the drive circuit. The vertical start signal STV is provided to a first stage of the stages to initiate a driving of the gate drive circuit.
Static electricity, which is generated during a manufacturing process of the mother substrate or an array test process, is applied to a pad receiving the vertical start signal STV so that the static electricity damages a first stage of the gate drive circuit. As the first stage of the gate drive circuit is operated, the remaining stages are sequentially operated. As a result, when the first stage is damaged by the static electricity, the gate drive circuit is not operated.